Telephone-exchange system



C. B. FOWLER. TELEPHONE EXCHANGE SYSTEM.

APPLICATION mm) SEPT- so, 1920.

Y //1 venfor: flare/m: 8 flaw/er by 'A/ry Patented Nov. 15, 1921.

i UNITED v STATES PATENT OFFICE.

cnannncn B. rownnn, or new YORK, n. Y., assrenon T wns'rnnn nnnc rnrc cony PANY, rnconronn'rnn, ornnw YORK, N. Y., A conrona'rron or nnw YORK.

TELEPHONE-EXCHANGE SYSTEM.

i i T 0 all whomiz' t may concern ,Be it known that I, CLzrRnNon B. Fownnn, a icitizen of the United States I'QSlClIDQ tLt New York city, in the county of New 1 ork and State of New York, have inventedre tain new anduseful Improvements in Telehone- Exchange Systems, of which the follbwing is .a full, clear, concise, and exact description, j

. This nvention relates to telephone exchange systems and particularly to systems of this nature in which common battery and local battery telephone lines terminate at a central oflice. l i t In such systems it is often necessary to entend a call received over a local battery line either to another local battery line or to. a common battery line, by means of an operators link or cord circuit.

In interconnecti ns ofthls nature it is desirable that the operator receive suitable supervisory signals to indicate that either of the. connected parties is signaling for a disconnection as well as to indicate the chary central office in some distinctive manner.

b g as quiring signaling devices additional to those The object of the resent invention is to provide an improv signaling means for telephone systems of this character in which various desirable supervisory signals are produced in a positive manner without rerequi :ed by the-ordinary link circuit used forinterconnecting lines of a similar char-i acter. H

In order to attain this object in accord: ance with one feature of thisinvention there is provided a so-called semimniversallink i q Signal circuit which is provided withsupervisory signaling devices associated with each end thereof and with means which causes the individual or cooperative functioning of these devices in response to the signals received from the local battery or commombattery lines, so as to provide distinctive d-iscon-j nectsignals for either character of lines,

as well as to provide a distinctive recall for the commonbattery line, which is effective in the absence of a signal from t call g ocaliba s y line,

i i I Specification of Letters Patent. Patented NOV. 15,1921. Application filed September 30. 1920. Serial li'o. 413.834. h i

The invention will be more clearly llIl-l derstood from the following description thereof and the accompanying .drawing, the figure of which shows one embodiment of the invention. a v

Referring to the drawing, alocal battery line circuit A terminates in a jack 10 and an associated signaling device 1L before an operator at whose position there .may be provided a plurality of link. circuits, D, adapted to lextend a call from the line circuit A to a local battery line circuit B or to a commonbattery line circuit C. A supervisory lamp associated with the answering plug 15 oft-he link circuit is adapted to be intermittently operated at a steady rate upon receiving a disconnectsignal from the subscriber on the line circuit A, as well as upon a similar signal from the subscriber on the line circuit B if the calling plug of y the linkcircuit is connected with ihe latter.

line. The supervisory lamp associated with the calling plug of the link circuit is adapted to be steadily illuminated in response to a disconnect signal 'from the "subscriber on the line circuit B whensocon-j nected to the link circuit D. Lamp 30 is also adapted to be steadily illuminatedon a disconnect signal from the subscriber on line C, and intermittently illuminated. on a ret-all signal from the same subscriber. If, however, the subscriber of line A signals before the subscriber ofline C, thenthe lamp 30 will be intermittently illuminated by either a recall or disconnect signal from the subscriber of line C. i

It is thoughtthat the invention may be more fully comprehended from the following description of the operation of thccin cuits shown in the drawing. The subscriber at the station on the line circuit A, desiring to signal the operator at the central oifice, actuates the hand generator at such station, which causes the operation 'of the drop or other signaling device 11. The operator, observing the signal inserts the plug 15 of one. of a plurality of cord circuits D located at her position, intothe jack10. The signalingdevice 11 is thereby rendered inefi'ective due to the opening of the normally closed contacts'of jack 10. Relay. 23 thereupon operates over a circuit extending from battery through the left-hand. winding of relay23, the sleeve contacts of plugj15 and jack 10, and thewresistance 12 to ground.

-The operator thereupon actuates the listen- "ing key 81, which connects the usual opjack 40 d sconnects thewinding of'the sigerators telephone set (not shown) with the operators cord circuit D. Upon ascertaining that the calling subscriber desires to converse with the subscriber whose station is connected with the line circuit B, the listening. key 31 is restored to normal and the calling plug 33 is inserted into the jack 10. e opening of the local normal contacts of naling device 41 from the conductors of the line circuit B. A circuit is also completed. extending from battery through the righthand winding of relay 23. the winding oi marginal relay26, the sleeve contacts oi plug 33 and jack 4E0, andfthe high resistance 42'to ground. 'Due to the high resistance of the resistance 42, marginal relay 26 receives insufficient current for its operation. Therefore, both windings of relay 27, in series, remain in'bridgerelation across the talking conductorsof the calling end of the cord circuit. v

.Upon the completion of the conversation, if the subscriber whose station is associated with the line'circuit A desires to transmit a disconnect signal. to the operator the actuationof the'hand generator at such station causes the flow of alternating current from the hand generatorover a circuit including I the tip and ring contacts of: jack 10 and plug 7 15 the normal, contacts of ringing key 21,

response to the current flowing from the and ,the right-hand winding of relay 22. In

hand generator, supervisory relay 22 op crates, and looks over a c rcuit, extending from battery through the contact of relay 23, the local contact of listening key 31, and the left-hand winding and left-hand contact of relay-22 to ground.- .A circuit is completed by the closure of the right-hand contactiof relay 22, which extends from battery through the winding of relay .16, the resistance 19, the lamp 20, and the right hand contact of relay 22 to ground. Lamp 20 is thereupon illuminated and relay 16 is operated. However, immediately upon the operation of relay 16, a, branch path is produced, which may be traced, from ground I throughthe interrupter 17, the right-hand contact of relay '16, and the resistance 18 to the upper terminal of resistance 19, where it joinsthe previously traced path. Lamp 20 is thereby flashed at a constant rate determined by the speed of rotation of the interrupter 17. The flashing of lamp 20 indicates to the operator that the subscriber whose station is connected with line A de sires to terminate the connection. However,

" the operator challenges the signal by actuating the listening key to ascertain positively front the subscriber whether a disconnect on is desired. The actuation of the ha tening key 31 causes the release of relay 2:2, the opening of the circuit of relay l6 and the lamp 20 which thereupon ceases to dash.

In case the subscriber whose station is on the line circuit 13 desires to signal the operator, the actuation of the hand generator thereat causes the flow of ringing current over a circuit which includes the line conductors, the tip and ring contacts of jack 40 and plug 33, the normal contacts of ringing key 32, the right-hand normal contact of relay-26, and both windings of relay 27 in series. The response of ringing response relay 27 causes the operation of relay 2 1 over a circuit extendin g from battery through the contact of relay 23, the normal contact of listening key 31, the winding of relay 24, the normal contact of relay 25, the alternate contact of relay 27, the resistance 28, and the lamp 30 to ground. Relay 2%, in operating looks over a circuit, including the middle contact thereof and in closing such middle contact relay 21 shunts the lamp 30 over a. path extending from ground through the middle contact of relay 24, and normal contact of relay 25, the alternate contact of relay 27 and the resistance 28 to the terminal of lamp 30. The lamp 230 is therefore prevented'from being lighted under this condition. However, as soon as the flow of: ringing current from the hand generator of the line circuit B cease-s, and the relay 27 releases, lamp 30 is illuminated through a circuit which may be traced from battery through the right-hand winding of relay 25, left-hand contact of relay 2 1', normal contact of relay 27, resistance 28, and lamp 30 to ground. Eelay'25 operates and locks up from battery through its'left-hand winding and contact and the right-hand contact of relay 24 to ground. The closure 01. the righthand contact of relay 2 1 completes a circuit which extends from battery through the winding of relay 16, the resistance 19, the lamp 20, the left-hand normal contact of re lay 26 and the right-hand contact of relay 24 to ground. Relay 16 immediately operates and completes a. shunt path including the interrupter 17, in the manner previously described, so that lamp 20 flashes at a constant rate as in thecase of thedisconnect sig nal being received from the subscriber whose station is connected with the line circuit A. Thus, as a' result of the disconnect signal rcceiyed over the local battery called line circuit, lamp 30is steadily illuminated and lamp 20 flashes constantly. The operator may thereupon challenge the signal, as in the previous case, by actuating listening key 31, and upon ascertaining that the called party desires to have the line disconnected from the cord circuit, both plugs 15 and are removedfrom the associated jacks and all a'pparatus is restored to normal.

In case the operator in answering a call reoeived over the line circuit A, as previously described, ascertains thatconnection is desired with the common battery subscribers line circuit C, theplug 33 is inserted into jack: 50. Theline relay .51 is disconnected from operative association with the line conductors by the opening of the normally 1 closed localcontacts of the jack 50, thereby reventing the illumination of the usual line amp 53. The resistance 52 is of a comparatively low value so that marginal relafy 26 now operates over a circuit extending rom battery through the right-hand winding of relay 23, the winding of relay 26, thesleeve contacts of plug 33 and 'ack 50, andthe resistance. 52 togronnd. v lhe opening of the right-hand normal contact of relay 26 removes the serially interconnected windings of relay 27 from the bridge relation across the talking conductors of thecalling end of the cord ClI'CllltD, whilethe closure of the left-hand inner andright-hand outer alterninate contacts of relay 26 connects ground and battery, at these contacts, respectively,

through the left-hand winding ofirelay 27 to the line conductors. A circuit is closed 1 through lamp which is illuminated, which circuit may be traced from batterythrough the right-hand winding of relay 25, which operates, the right-hand inner contact of relayl26, normal contact of relay 27, resistance 28 and lamp 30 to ound, The operator may then actuate t e ringing key 32, causing ringing current to flow from the source through the lower alternate contact of key 32, the ring contacts of plug .33 and jack 50,1the signaling bell at the station on the line circuit C, thetip contacts of jack and plug 33, and the uppfir alternate contact of key 32 to ground; 1 e called subscriber, in responding to the signal produced by the rin er removes the receiver from the switchhoo completing the line circuit so that relay 27 is operated over a circuit extending from battery through the right-hand outer alternate contact of relay 26, the left-hand winding of relay 27 the lower normal contact of ringing key 32, the ring contacts of plug 33 andjack 50, thetelephone apparatus at the station on the line circuit C, the tip contacts of jack 50 and plug 33, the upper normal contact of ringing key 32, and the lefthand inner alternate contact of relay 26 to ground. In operating, relay 27 opens the circuit previously traced through lamp 30 and the right-hand winding of relay 25. Lamp 30 is extinguished and relay 25 releases. Relay 27 also completes a circuit extending from battery through the contact of relay 23, the local normal contact of listening key 31, the winding of relay 24, the normal contact of relay 25, the alternate contact of relay 27, the resistance 28, and the lamp 30 to ground. Relay 24 immediately operates and looks over the circuit previously mentioned therefor, and in closing its right-hand contact,ishunts the lamp 30 by the resistance 28, thercbypreventing the illumination of such larpjp. a pon the completion of the conversation, ii the called party desires to signal theop erator for a disconnection, the receiver is placed on the hook, thus opening the line circuit and allowing relay 27 to release. A

circuit may then be traced from battery.

through the right-hand winding of relay 25,. the lefthand contact ofrelay 24, the normal contact of relay 27, the resistance 28,and the lamp 30 to ground. Relay 25 thereupon looks through its left-hand winding. so that the lamp 30 is steadily illuminated over a circuit which includes the righthand winding of relay 25. 1

Upon observing the steadily illuminated condition of lamp 30, the operator may remove the .plug 33 from the jack 50, and upon ascertaining that the subscriber, whose line is connected with the answering end of the; cord circuit, has completed the conversation, the latter-mentioned plug may also be removed and all apparatus restored to normal.

'Inf caseithe SllbSCllbGl on the common batteryline circuit C desires to recall the operator, to indicate that another call is desired to be extended or that the other connected party should be recalled, the subscriber may remove the receiver from the switchhook, causing the reoperation of relay 27 over the circuit previously traced therefor, so that relay 16 is now connected in circuit with thelamp 30 over a path extending from battery through the winding of relay 16, the right-handalternate con tact of relay 25, the alternate contact of re- .lay 27, the resistance 28, and the lamp 30 to ground. Immediately uponthe operation of relay 16, a circuit is also formed which extends from ground through the interrupter' 17, the left-hand alternate contact of relay 16, the left-hand alternate contact of relay 26and resistance 29to the terminal. of the lamp 30. Therefore, as long as the sub scribers receiver remains off the hook, the

which may be traced from ground through the interrupter 17, left-hand alternate contacts of relays 16 and 26 and resistance 29 of both lines-have signaled and that the called line, is of the Thus it may be be'seen that with the two supervisoryVisig'naling devices becoming as- 1 sociated with either end of the cord circuit,

a disconnect signal "from the calling local battery line produces a flashing ofthe asline circuit connected with'the:

sociated' answering lamp while a similar disconnect signal from called local battery line produces a'similar flashing of the same lamp and the steady illumination of the supervisory-lamp associated \viththe calling endflof the cord circuit; 7 When there is no signal from thecalllng sub scriber s lin'eQthe disconnectgsignal, beingtransmitted from the common battery calling 'end of thecord ClI'CllltfOfillSBS the steady illumiline circuit,

upon a disconnect signal being received from a local battery line. Iffhowever, the calling subscriber has previously signaled; then, as

explained above, both lamps will flashinswering supervisorysifgnallng device con trolled over one Vjcharacter,

"termittently upon either a disconnect; or a recall signal from the called common'bat- 'teryiline e n I VVhat isclaimed is: a

1. In .a telephone" exchange system, telephone lines of various characteristics, allnk c rcuit for interconnecting the, lines, an an? of called line,a calling {supervisory signaling device controlled over each character of called line and means to cause said answering and calling supervisory signaling devices to indicate by itheirjoint action the character of a called line signaling for; a disconnection.

2. ,n In a'telephon'e exchange system, common-battery and local battery telephone line's, a link circuit for interconnecting the lines; an answering supervisory signaling common battery type.-

displayed, the character otthe line and the nature of the signal,

4/111 a telephone exchange system, common battery and local battery telephone lines, a link circuit for interconnecting'tlie lines, 2111' answeringsupervisory signaling device controlled overa called local battery line, a calling supervisory signaling device controlled over a called line said signaling devices cooperating on a. signal from a called line to indicate the character ofthe line. 1' i i In a. telephone exchange system, common batteryand local battery telephone lines,'.a link circuit for interconnecting the lines, anlzanswering supervisory signaling device cont'rolledover a called local batter line, a relay associated.with the calling end of said link circuit responsive to current over the called line, and means responsive to theactuation 'of said relay and to the ('OllllG'CtlOll"Oi the calling end; of the link circuit withthe localbattery line to cause the display of said answering supervisory signaling deviceiwhen the calling end of said link circuitisconnected with a local battery line. :1 v 1 i In witnesswhereof, I hereunto subscribe my name this 27th day of September A.

of either character, 

